Chi-Squared test for binomial distribution

[lucrob]

Attempted this question and got the wrong P-Val and Chi-squared statistic.

The question asks to conduct a chi-square goodness of fit test for the binomial distribution in this set of data:


My attempt at the question:
H₀ : Data is binomially distributed
H_A : Data is not binomially distributed
df: 8 - 3 = 5

The expected value of a binomial distribution is: E(x) = np
Since E(x) = 4.20664 (calculated from the data): 4.20664 = 7p
probability = 0.600949

X~B(7, 0.600949)

After I found the binomial distribution for the data set I calculated the expected values for each day by taking the probability x the total number of students (in this case being 271)

Then used my calculator to conduct a chi-squared GOF test and found that:
Chi² statistic: 251.759
PVal: 2.3045932713742 x 10^-52

The answer key states:
Chi² statistic: 135
PVal: 2.43 x 10^-27

I manually calculated the Chi-squared statistic but still got the incorrect answer (251.759) so from that, I concluded that I went wrong in the binomial distribution section but I'm not too sure where. Another possibility is that the HAESE textbook I am using has the wrong answer. Although, I have no way of knowing.

Any help or validation of my answer would be much appreciated. Many thanks.

 

[Prof]

I think Ho must include a value for p. You do not find p from your data. (It is a theoretical parameter, not a sample statistic.) For example, Ho might state that the distribution is binomial with p = 0.6. Check to see if the question in the book specifies a value for p. Since your answer is so close to what the book says, maybe they used p = 0.6.